The present invention relates to an airborne-sound sealing arrangement for an opening in the body of an automobile and a shift lever which extends through this opening.
From German Published Unexamined Patent Application No. 2,353,417, a gear shift lever for a motor vehicle has become known that is arranged in an opening of the body. This gear shift lever is tightly closed off with respect to the interior of the vehicle via bellows that tightly enclose the shift lever. By means of this type of an arrangement of bellows above one another, a sealing-off of the interior of the vehicle with respect to airborne sounds is achieved. However, this is possible only to an insufficient degree, and a disadvantageous structure-borne noise bridge may be created. It is also known to close the opening off with a sound-absorbing part made of a foamed material, which, however, requires an expensive, precisely machined part.
It is an objective of the present invention to provide an improved sound sealing arrangement for an opening for a pivotal gear shift lever in which for conditionally moved parts within an opening, an improved sealing-off of airborne noise with respect to the interior of the vehicle is achieved and a structure-borne noise transmission is also avoided, and in which impairments of the shifting paths are prevented.
This and other objects of the invention are achieved by providing a sound sealing arrangement in which a sound insulting means is arranged in an opening in the vehicle body between a shift lever and the vehicle body. The sound insulating means tightly encloses the shaft of the shift lever, and is filled with a flowable medium.
Advantages achieved by means of the present invention include that because of the reflection of the sound waves at the boundary layer between the surrounding medium of air and the sound-absorbing shell (rubber and fluid), the largest part of the airborne sound is reflected and thus cannot penetrate into the interior of the vehicle. For this purpose, a tight sealing between the cutout on the side of the body and gear shift lever that is moved in it is required.
For this purpose, the shell of the element, irrespective of the position of the gear shift lever, rests tightly against the body. In every position of the gear shift lever, a sufficiently thick layer of the liquid medium will always exist so that over the whole surface of the cutout, an identical sealing-off of airborne noise is ensured.
By means of the relatively soft, flexible design of the medium-filled insulating element, a structure-borne noise transmission between the vibrating unit (such as the center tube) and the body of the vehicle is prevented. No forces and thus no vibrations can be transmitted in the direction of the body. For this purpose, the shell of the element is designed in such a way that the gear shift lever movements are unimpaired and no tight connection exists between the tube and the body. In addition, because of the unstressed filling of the interior space with liquid medium, no tensile stress is created during shifting at the outer shell and excess pressure is prevented in the interior space so that the shifting forces are not impaired.
By means of the flexibly designed element, installation tolerances are absorbed so that the cutout, as well as the opening, need not be aligned precisely with respect to one another, as is required for known sound-absorbing parts made of foamed material arranged in the cutout. The insulating element also makes it possible within certain limits to absorb a shaking of the shift rod by means of the displacing of the liquid medium in the element.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.